JP5723291B2 - Method for producing a splice joint between two optical fibers - Google Patents

Description

  The present invention relates to a splice joint between two optical fibers, the two optical fibers each having a fiber core and a fiber sheath positioned adjacent to the fiber core. . The present invention further relates to a method of making such a splice joint.

  If the fiber is designed to lead to a high light output with high beam quality, there is the disadvantage of increased sensitivity to misalignment and bending, which results in disadvantages being guided, for example, in the fiber core An increase in light loss may occur and / or undesirable coupling between different modes guided within the fiber core may occur.

  In addition, during the splicing operation, the high energy supply made in the region of the ends to be spliced can cause a change in the waveguide properties of the fiber, which results in this region. For example, undesired coupling-out of some of the guided radiation occurs. This can result in unacceptably high thermal loads on the fiber sheath, which is often realized as a polymer protective sheath. If the fiber core is a two-core fiber having an internal signal core and a pump core surrounding the internal signal core, radiation coupled from the internal signal core can propagate over a long distance within the pump core. However, in order to achieve the desired beam quality, in many cases only radiation from the internal signal core needs to exit at the end of the entire fiber run, so that the radiation guided in the pump core is Impairs beam quality.

  In view of the above, it is an object of the present invention to provide an improved splice junction between two optical fibers. Furthermore, a corresponding method for making such splice joints shall also be provided.

  This object is in accordance with the present invention a splice junction between two optical fibers, each of the two optical fibers having a fiber core and a fiber sheath positioned adjacent to the fiber core. For at least the first fiber, the fiber sheath is completely removed at a connection region extending along a predetermined length from the splice end of each fiber in the longitudinal direction of the fiber, and a support sleeve is provided, the support sleeve Is arranged with a splice end of two fibers, the support sleeve extends at least along the entire connection region of the first fiber, beyond the connection region, beyond the fiber sheath of the first fiber, The portion of the support sleeve that extends beyond the fiber sheath of the fiber is the first flange. Achieved by a splice joint that is not located adjacent to the fiber sheath of the Iber and is mechanically connected to the fiber core of the first fiber, either directly or via an intermediate sleeve, in the connection region of the first fiber Is done.

  Mechanical contact between the support sleeve and the fiber core of the first fiber makes it possible to achieve mechanical stabilization of the splice joint, thereby causing undesired bending of the fiber core of the first fiber. Is prevented. In addition, the support sleeve can extend beyond the sheath of the first fiber, thus protecting the splice joint from contamination. Furthermore, in the case of the splice joint according to the invention, the support sleeve is not located adjacent to the fiber sheath itself and does not need to be connected to the fiber sheath, so that the fiber sheath is not subjected to a thermal load in realizing the splice joint. .

  The sheath of an optical fiber here refers specifically to the part of the fiber that is not subject to thermal loading and is therefore removed from the fiber before the fiber ends are spliced together. Thus, in the sense of the present invention, the sheath is in particular a protective sheath for optical fibers. In this case, the fiber core is in particular the rest of the fiber. The fiber core in particular serves to guide the light and can be configured in various ways to achieve the required optical guiding function. The fiber generally includes a signal waveguide core (eg, made of glass material) and a glass material sheath that surrounds the core and ensures the guiding of light within the signal core. In the case of a two-core fiber, the sheath in this case constitutes a so-called pump core in which so-called pump light is guided in the sheath, for example. Thus, the fiber core here refers in particular to the part of the optical fiber that remains when the protective sheath is removed, which fiber core generally consists of a glass material with different doping and, where appropriate, also an internal void.

  In the case of a single core fiber, the core of the single core fiber and the sheath of the single core fiber are here a fiber core within the meaning of the present invention, and the sheath is a protective sheath of the single core fiber within the meaning of the present invention.

  In the case of a two-core fiber, for example, the core and the so-called clad constitute a core within the meaning of the present invention, and the sheath of the two-core fiber is a sheath within the meaning of the present invention. Obviously, the cladding may also be removed. In this case, the clad and sheath of the two-core fiber constitute a sheath within the meaning of the present invention, and the core of the two-core fiber is a core within the meaning of the present invention. The same applies for example to fibers with 3 or 4 cores or other fibers with at least one core and one sheath.

  In particular, the fiber core is made of glass, for example, and usually refers to the portion of the fiber that guides light or electromagnetic radiation. The electromagnetic radiation in this case is in particular electromagnetic radiation of the visible spectrum (for example 380 nm to 780 nm) and the adjacent infrared electromagnetic spectrum (780 nm to 2500 nm).

  The support sleeve is preferably implemented as a rigid or rigid support sleeve that provides the desired protection against bending and twisting.

  The protective sleeve can be made from the same material as the fiber core. In particular, the protective sleeve can be made from quartz glass.

  The mechanical connection between the support sleeve and the intermediate sleeve or fiber core is in particular a connection by shape locking and / or material bonding. The same applies to the connection between the intermediate sleeve and the fiber core.

  The mechanical connection can in particular be brought about by a local heat supply. In particular, laser radiation can be used for this purpose, whereby the support sleeve or intermediate sleeve is fused onto the fiber core.

  In the case of a splice joint according to the invention, the part of the support sleeve that extends beyond the first fiber fiber sheath can be prevented from being mechanically connected to the fiber sheath, apart from the end face seal that is optionally provided. . This achieves the advantage that no heat supply is required in this part, so that thermal damage to the fiber sheath can be prevented. The end face seal can be made from the same material (eg, polymeric material) as the fiber sheath material in particular.

  In the region of mechanical connection, the support sleeve can have an inner diameter that is smaller than the inner diameter of the portion of the first fiber that extends beyond the fiber sheath. Thus, the support sleeve can have a varying inner diameter. In particular, the thickness of the support sleeve is constant. However, the thickness of the support sleeve can also vary along the length of the support sleeve.

  In the case of the splice joint according to the invention, the fiber sheath can be completely removed in each of the connection areas for both fibers, and the support sleeve exceeds the connection area along the entire connection area of the second fiber, The portion of the support sleeve that extends beyond the fiber sheath of the second fiber and then extends beyond the fiber sheath of the second fiber is not located adjacent to the fiber sheath of the second fiber. Such a support sleeve ensures excellent mechanical stability of the splice joint. Furthermore, the splice joint can be sufficiently protected against contamination.

  In the connection region of the second fiber, the support sleeve can be mechanically connected directly to the fiber core of the second fiber or via an intermediate sleeve. In particular, it is possible to provide a mechanical connection in both the connection region of the first fiber and the connection region of the second fiber. In particular, the mechanical connection can extend beyond the splice end.

  Advantageously, the portion of the support sleeve that extends beyond the fiber sheath of the second fiber can be prevented from being mechanically connected to the fiber sheath, apart from optionally provided end seals.

  When the support sleeve is mechanically connected directly to the fiber core, the refractive index of the support sleeve is such that the light guided in the fiber core can be coupled out to the support sleeve via a direct connection. You can choose. For this reason, the refractive index of the support sleeve can be constant or it can vary spatially. Essential in this case is that the light guided in the fiber core can be at least partially coupled to the support sleeve.

  When the support sleeve is mechanically connected to the fiber core via the intermediate sleeve, the refractive index of the support sleeve (including any refractive index variation) and the refractive index of the intermediate sleeve (including any refractive index variation) are: The light guided in the fiber core can be selected to be output coupled to the support sleeve via the intermediate sleeve.

  In particular, the support sleeve can be realized as a volume scatterer. Thus, since the support sleeve material includes, for example, scattering particles, the support sleeve material has a high scattering effect on the input coupled light. As a result, out-coupled light can be emitted into the atmosphere over a larger spatial area, thus reducing the heat load per area.

  Additionally or alternatively, the support sleeve can be realized as a surface scatterer. This can be realized, for example, by roughing the surface.

  The intermediate sleeve (s) can likewise be realized as volume scatterers and / or surface scatterers.

  Obviously, the refractive index (s) can also be selected to minimize the output coupling of light from the fiber core.

  The support sleeve can in particular be realized as a single support sleeve. At least one intermediate sleeve can also be realized as a single body in each case. Furthermore, the at least one intermediate sleeve can be made from the same material as the support sleeve.

  In the case of the splice joint according to the invention, apart from the intermediate sleeve (s) provided in some cases, between the support sleeve and the exposed fiber core (eg curable lacquer or resin, heat-shrinkable tube etc. No further connecting means (such as) are arranged.

  Furthermore, a method for producing a splice joint between two optical fibers, each of the two optical fibers having a fiber core and a fiber sheath positioned adjacent to the fiber core, wherein at least one of the two fibers For the first fiber, the fiber sheath is completely removed in the connection region extending along the length from the end of each fiber to be spliced in the longitudinal direction of the fiber, and the support sleeve is removed from the two fibers. Pushed into one side, the two ends of the fibers to be spliced are aligned and spliced together, then the support sleeve is placed so that the splice ends of the two fibers are placed in the support sleeve and A portion of the support sleeve extending beyond the fiber sheath of the first fiber Without being adjacent to the fiber sheath of the first fiber, the support sleeve extends beyond the connection region along at least the entire connection region of the first fiber and beyond the fiber sheath of the first fiber. In addition, a method is provided in which the support sleeve is mechanically connected directly to the fiber core of the first fiber or via an intermediate sleeve in the connection region of the first fiber by pushing into the splice end.

  The method according to the invention makes it possible to produce a splice joint in which the splice fiber is protected against bending and twisting and contamination in the region of the splice end.

  The mechanical connection between the support sleeve and the intermediate sleeve or fiber core can be realized as a connection by shape locking and / or material bonding. In particular, the connection can be realized by a heat supply. In particular, a laser can be used for this purpose.

  In the case of this method, the portion of the support sleeve that extends beyond the fiber sheath of the first fiber can be prevented from being mechanically connected to the fiber sheath, apart from the optional end face seal. As a result, the fiber sheath is not subject to excessive heat loads.

  Further, the fiber sheath can be completely removed in each of the connection regions for both fibers, and the portion of the support sleeve that extends beyond the fiber sheath of the second fiber is the fiber of the second fiber. Without being located adjacent to the sheath, the support sleeve can be pushed into the splice end so that it extends beyond the connection region along the entire connection region of the second fiber and beyond the fiber sheath of the second fiber. it can. In particular, in the connection region of the second fiber, the support sleeve can be mechanically connected directly to the fiber core of the second fiber or via an intermediate sleeve. The portion of the support sleeve that extends beyond the fiber sheath of the second fiber can also be prevented from being mechanically connected to the fiber sheath, apart from optionally provided end seals.

  These steps make it possible to produce a splice joint having the desired properties.

  Furthermore, when the support sleeve and fiber core are directly mechanically connected, the refractive index of the support sleeve is such that the light guided in the fiber core is coupled out to the support sleeve via the direct connection. You can choose. Similarly, when the support sleeve is mechanically connected to the fiber core via the intermediate sleeve, the refractive index of the support sleeve and the refractive index of the intermediate sleeve are such that the light guided in the fiber core passes through the intermediate sleeve. Through the support sleeve.

  This ensures that the radiation exiting at the seamed end region is diverted outward without compromising the beam quality, and the heat, for example to the fiber sheath, due to the radiation exiting at the seamed end region. Damage can be prevented.

  In the case of this method, the support sleeve can be realized as a volume scatterer and / or a surface scatterer. The same applies to the intermediate sleeve (s). Furthermore, in the case of this method, it is possible to use a single support sleeve as the support sleeve.

  In the case of the method according to the invention, before joining the two fibers, an intermediate sleeve can be pushed into one of the two fibers, and after joining the two fibers, the fiber core of the first fiber is intermediate The sleeve is mechanically connected and then the support sleeve is mechanically connected to the intermediate sleeve. Obviously, if multiple intermediate sleeves are provided, the sleeves are pushed into one of the two fibers before they are spliced together, and the sleeves, for some of them, to the support sleeve Connect to the corresponding fiber core before connection. However, it is possible to first connect the support sleeve to the intermediate sleeve (s) and then connect the intermediate sleeve (s) to the fiber core (s).

  The mechanical connection between the intermediate sleeve (s) and the fiber core (s) is preferably made in a material-bonded and / or shape-locked manner. In particular, the connection is provided by a heat supply. In particular, laser radiation can be used for this purpose.

  It will be understood that the features described above, and the features not yet described, are applicable not only in the combinations described, but also in other combinations or alone, without departing from the scope of the present invention.

  The invention will now be described in more detail by way of example with reference to the accompanying drawings, which also disclose essential features of the invention.

1 is a schematic cross-sectional view of a splice joint according to the present invention according to a first embodiment. It is sectional drawing explaining preparation of the splice junction part of FIG. It is sectional drawing explaining preparation of the splice junction part of FIG. It is sectional drawing explaining preparation of the splice junction part of FIG. It is sectional drawing explaining preparation of the splice junction part of FIG. It is sectional drawing explaining preparation of the splice junction part of FIG. It is sectional drawing explaining the modification of a manufacturing method. FIG. 6 is a schematic cross-sectional view of a splice joint according to a further embodiment. FIG. 6 is a schematic view of a splice joint according to a further embodiment. FIG. 6 is a schematic view of a splice joint according to a further embodiment. FIG. 6 is a schematic view of a splice joint according to a further embodiment. FIG. 6 is a schematic view of a splice joint according to a further embodiment. FIG. 6 is a schematic view of a splice joint according to a further embodiment. FIG. 6 is a schematic view of a splice joint according to a further embodiment. FIG. 6 is a schematic cross-sectional view of a splice joint according to a further embodiment.

  In the case of the embodiment shown in FIG. 1, the splice joint 1 according to the invention comprises a first optical fiber 2 and a second optical fiber 3 which are spliced together. Since the two fibers or optical waveguides 2 and 3 have the same structure, only the first fiber 2 will be described in detail below.

  To enhance the clarity of the figure, the depiction of FIG. 1 and the following unexplained figures is not to scale. Further, in order to obtain a clearer sectional view, most of the hatching lines that are normally used are omitted in FIG. 1 and the following drawings.

  The first fiber 2 has a fiber core 4 and a protective sheath or fiber sheath 5 surrounding the fiber core 4. The fiber core 4 includes an internal signal core 6, and the internal signal core 6 is surrounded by a signal core sheath 7 (hereinafter referred to exclusively as a sheath 7). The fiber core 4 is made of quartz glass doped differently from the signal core 6 and the sheath 7, and the signal light is transmitted into the signal core 6 due to a difference in refractive index between the signal core 6 and the sheath 7. Can be guided.

  The fiber sheath 5 is realized as a polymer protective sheath 5 and its refractive index is selected so that light can be guided in the sheath 7 as long as desired.

  As can be seen from FIG. 1, the fiber sheath 5 is completely removed in the first connection region 8. The connection region 8 extends from the splice end 9 of the first fiber 2 along the longitudinal direction of the first fiber 2 by a predetermined length (about 10 mm in this case), so that the signal core sheath 7 is the first core 2. The connection region 8 is exposed. Furthermore, from FIG. 1, in the second connection region 10 extending longitudinally from the splice end 11 of the second fiber 3 along a predetermined length (again approximately 10 mm here), the second fiber 3 also shows that the fiber sheath 5 has been completely removed so that the signal core sheath 7 is fully exposed in the second connection region 10.

  The splice joint 1 further includes a support sleeve 12 made of quartz glass, which extends laterally beyond both the connection regions 8, 10. The support sleeve 12 has a substantially constant wall thickness of approximately 30 μm to 200 μm, but its inner diameter varies in the longitudinal direction. Thus, the support sleeve 12 has a central portion 13 having a first inner diameter. Adjacent to each side of the central portion 13 are connecting portions 14, 15 having gradually increasing inner diameters, which are gradually connected to edge portions 16, 17 having a constant inner diameter larger than the inner diameter of the central portion 13, respectively. It has transitioned to.

  The central portion 13 is connected to the fiber core 4 or signal core sheath 7 of the two fibers 2, 3 in a shape-locking and material-bonding manner, but the two edge portions 16 and 17 extending beyond the fiber sheath 5 are Since the inner diameter is selected to be (slightly) larger than the outer diameter of the fiber sheath 5, it is at a certain distance from the fiber sheath 5. Accordingly, there is a gap S between the edge portions 16 and 17 and each fiber sheath 5. Therefore, the inside of the edge portions 16 and 17 is not located adjacent to each fiber sheath 5.

  In order to protect the connection regions 8 and 10 from contamination, the rings 18, 19 made of the same material as the fiber sheath 5 and sealing the gap S between the respective edge portions 16 and 17 and the fiber sheath 5 are rigid or Attached to both axial ends of the rigid support sleeve 12. Thus, except for the rings 18, 19, there is no connection of the edge portions 16, 17 to each fiber sheath 5 and thus to the corresponding fibers 2, 3.

  Therefore, the support sleeve 12, which can also be referred to as a support tube, is a waisted support sleeve 12 because the inner diameter of the central portion 13 is smaller than the inner diameters of the edge portions 16, 17.

  The connection between the central part 13 of the support sleeve 12 and the fiber core 4 in the connection regions 8 and 10 is mechanically stabilized in the splice joint 1 of the two fibers 2, 3 by the connection by means of shape locking and material bonding, Protected against unwanted bending or twisting. This protection against bending or twisting is further enhanced by the two edge portions 16, 17 overlapping the polymer protective sheath 5.

  The fibers 2 and 3 shown in FIG. 1 are so-called single-core fibers. However, the fibers 2 and 3 in FIG. 1 can also be realized as a two-core fiber. In this case, the fiber core sheath 7 constitutes a so-called pump core 7 in which pump light is guided. For this reason, the protective sheath 5 has a refractive index that can ensure the guiding of the pump light.

  By selecting the refractive index of the quartz glass from which the support sleeve 12 is made to be equal to or greater than the refractive index of the fiber core sheath 7, that is, the pump core 7, It allows the radiation directed in the fiber core sheath 7, ie the pump core 7, to be intentionally polarized from the fibers 2, 3. The refractive index of the quartz glass of the support sleeve 12 can be constant or can be varied spatially.

  Furthermore, the support sleeve 12 can be realized to have the properties of a volume scatterer. This can be realized, for example, by including scattering particles in the quartz glass of the support sleeve 12. Additionally or alternatively, the outer surface of the support sleeve can have scattering properties (eg in that the outer surface is roughened), thereby lengthening the radiation polarized from the fibers 2,3. It can be scattered or radiated in a distributed manner in the atmosphere over a distance, and radiation does not exit from the end face of the support sleeve at a high power density.

  In the case of the fibers 2 and 3 shown in FIG. 1 realized as a two-core fiber in which the radiation propagates not only in the internal signal core 6 but also in the pump core 7, in order to achieve the desired beam quality, in many cases At the end of the entire fiber travel, radiation needs to exit only from the internal signal core 6. In the case of the splice joint 1 according to the invention, advantageously, radiation from the pump core 7 is polarized from the fiber via the support sleeve 12 in the region of the splice ends 9, 11, ie in the two connection regions 8, 10. Can be made.

For example, if the first fiber 2 is an active two-core fiber, advantageously the pump light that is not absorbed by the internal signal core 6 of the first fiber 2 during propagation in the fiber core 4 is supported according to the invention. The sleeve 12 allows polarization from the fiber 2 at the end of the active two-core fiber 2 in the region of the splice ends 9, 11 , whereby the fiber travel leading to the active fiber 2, ie the second fiber 3. Prevent unacceptably high heat loads.

  Alternatively, the refractive index of the quartz glass of the support sleeve 12 can be selected to be smaller than the refractive index of the fiber core sheath 7 or the pump core 7. As a result, in the region of the connection regions 8 and 10, the pump light is guided in the pump core 7, for example by the central part 13, so that the splice junction according to the invention allows the pump light to pass through the first fiber 2 Can pass through the second fiber 3 with substantially no output loss. Preferably, the refractive index of the quartz glass of the support sleeve 12 is equal to or smaller than the refractive index of the polymer protective sheath 5.

  The splice joint 1 shown in FIG. 1 can be manufactured as follows. For example, from the two ends to be spliced (FIG. 2) of the fibers 2, 3 respectively brought about by breaking the fiber, the fiber sheath 5 of each fiber 2, 3 is in each case along a predetermined length. remove. This can be done, for example, by cutting, etching, or engraving and breaking using a laser (eg, a femtosecond laser). The ends to be spliced of the two fibers 2, 3 are cleaned, polished or otherwise trimmed if necessary.

  If desired, each of the exposed fiber cores can be rebroken or cut and polished, if appropriate, to produce an end to be spliced having the desired properties. This can be done, for example, by cutting using lasers (eg femtosecond lasers) or by engraving and breaking.

  After exposing the fiber core 4 in this way (FIG. 3), the support sleeve 12 is pushed into one of the two fibers 2, 3. In the case of the example embodiment described herein, the support sleeve 12 does not extend to the exposed fiber core 4 relative to the second fiber 3 but is still completely within the region of the fiber sheath 5 still present. It is pushed in to the position (FIG. 4).

  The support sleeve 12 can be pushed into the second fiber 3 before or after exposing the fiber core 4 but before trimming the end to be spliced.

  Thereafter, the two free ends of the fiber core are aligned and seamed together in a known manner (FIG. 5).

After splicing, the support sleeve 12 is pushed into the splice ends 9, 11 so that both sides extend beyond the connection regions 8, 10 and thus overlap the fiber sheath 5 (FIG. 6).
In this state, the central portion 13 of the support sleeve 12 is then shrunk (collapsed) onto the exposed fiber core by a fusion process, thereby creating a connection by shape locking and material bonding. In this case, the connecting portions 14 and 15 and the edge portions 16 and 17 are removed from the fusion process so that there is no thermal damage to the polymer protective sheath 5.

  Rings 18 and 19 are then realized and, if desired, the outer sheath surface of support sleeve 12 is roughened, thereby obtaining the splice joint shown in FIG. Obviously, the outer sheath surface can also be roughened in an earlier step or before being pushed into the second fiber 3.

  In order to minimize the supply of heat required for crushing the central portion 13 to the fiber core 4, the support sleeve 12 is pre-adjusted to the extent that the change in diameter necessary for crushing the fiber core is minimized. Can be arranged. In this case, the inner diameter of the central portion 13 may already be smaller than the outer diameter of the fiber sheath 5 of the second fiber 3. In this case, the support sleeve 12 cannot be pushed completely into the fiber sheath 5 as shown in FIG. 4, but can only be pushed partially as shown in FIG. In other respects, the steps of making the splice joint correspond to the steps shown in FIGS.

  FIG. 8 shows a second embodiment of the splice joint 1 according to the invention, which is shown in FIG. 1 in that the inner diameter of the support sleeve 12 is generally constant over its entire length. Different from the embodiment. In addition, a quartz glass stiff or rigid intermediate sleeve 20 is provided that is connected to the two fiber cores 4 in the region of the splice ends 9, 11 in a shape-locking and material-bonding manner. The support sleeve 12 is connected to the outer sheath surface of the intermediate sleeve 20 with a part of the support sleeve 12 by a shape lock type and a material bonding type. Thus, there is a mechanical connection between the support sleeve 12 and the fiber core 4 via the intermediate sleeve 20. The edge portions 16, 17 of the support sleeve 12 that overlap the fiber sheath 5 are at a distance from the fiber sheath 5, as in the embodiment of FIG.

  In the cross-sectional view of FIG. 8, only the intermediate sleeve 20 is shown by hatching lines for simplicity of illustration. Similarly, in the following description of example embodiments, only the intermediate sleeve is shown with hatched lines for simplicity of illustration.

  Obviously, in making the splice joint of FIG. 8, both the intermediate sleeve 20 and the support sleeve 12 are pushed into at least one of the two fibers 2, 3 before splicing the two fibers 2, 3. In this case, both sleeves 12, 20 can be pushed into the same fibers 2, 3, or the intermediate sleeve 20 can be pushed into one of the two fibers 2, 3, and the support sleeve can be pushed into the two fibers 2, 3 Can be pushed into the other.

  After joining the two fibers 2 and 3, the intermediate sleeve 20 is first moved to the position shown in FIG. 8 and crushed on the fiber core 4. Next, the support sleeve 12 is moved to the position shown in FIG. 8 and crushed on the intermediate sleeve.

  FIG. 9 shows a variation of the splice joint shown in FIG. Unlike the splice joint of FIG. 8, in the case of FIG. 9, two intermediate sleeves 21 and 22 are provided, in which case one of the intermediate sleeves 21 and 22 is arranged in one of the two connection areas 8 and 10, respectively. Is done. The intermediate sleeves 21 and 22 are realized in the same way as the intermediate sleeve 20, apart from their geometric dimensions, and here again are connected to the corresponding fiber core 4 in a shape-locking and material-bonding manner. The The support sleeve 12 is connected to the two intermediate sleeves 21 and 22 by a shape lock type and a material bonding type. In this embodiment, as in the subsequent embodiments, the intermediate sleeve is first connected to the fiber core and then the support sleeve is connected to the intermediate sleeve.

  FIG. 10 shows an example embodiment in which two fibers 2 ′, 3 ′ having very different diameters are spliced together. The fibers 2 'and 3' are constructed in essentially the same manner as the fibers 2 and 3 of the example embodiment described with respect to Figs.

  In the example embodiment of FIG. 10, the support sleeve 12 tapers stepwise from the thicker fiber 2 'to the thinner fiber 3'. Thus, in this example embodiment, the two edge portions 16 and 17 of the support sleeve 12 have different inner diameters that match the outer diameters of the two fibers 2 'and 3'. In the example of this embodiment, likewise, the inner diameter of each edge portion 16, 17 is always (somewhat) larger than the respective outer diameter of the fiber sheath 5 of the corresponding fiber 2 ', 3'.

  Further, the central portion 13 of the support sleeve 12 is connected to the fiber core sheath 7 or the pump core 7 of the fiber 2 ′ by a shape lock type and a material bonding type. Therefore, when realized as the pump core 7, for example, a desired output coupling of pump light can be ensured.

  FIG. 11 shows a variant of the embodiment of FIG. 10, which comprises an intermediate sleeve 23 connected to the fiber core 4 of the fiber 2 ′ in a shape-locking and material-bonding manner. The only difference is that it is arranged between the central part 13 of the support sleeve 12 and the fiber 3 ′ in the two connection regions 10. The intermediate sleeve 23 is realized in the same way as the intermediate sleeve 20, apart from its geometric dimensions. The central part 13 of the support sleeve 12 is connected in part to the intermediate sleeve 23 in the same way here in a shape-locking and material-bonding manner.

  FIG. 12 shows a variant of the embodiment of FIG. 11, in which the central part 13 and the connecting part 15 and the edge part 17 have the same inner diameter. Further, a support disk 24 is provided, and the support disk 24 has a central bore 25 whose inner diameter is larger than the outer diameter of the fiber sheath 5 of the fiber 3 '. Further, the support disk 24 has an outer diameter such that the left end surface 26 of the support sleeve 12 contacts the inner side 27 (facing the support sleeve 12) of the support disk 24. The end face 26 is connected to the inner side 27 by a shape lock type and a material bonding type. Due to the constant inner diameter of the central part 13, the connecting part 15 and the edge part 17, the axial length of the intermediate sleeve 23 can be chosen to be longer than is possible in the embodiment of FIG.

  By connecting the support sleeve 12 and the support disk 24 by material bonding, the support sleeve 12 and the support disk 24 together form a two-part support sleeve.

  In the case of the splice joint variant of FIG. 12, shown in FIG. 13, a second support disk 28 is provided, which is shape-locked on the right end surface 29 of the support sleeve 12. And a central bore 30 connected in a material-bonded manner and having an inner diameter somewhat larger than the outer diameter of the fiber sheath 5 of the fiber 2 '. Thus, in this embodiment, the support sleeve 12 can have a constant inner diameter over its entire length. Thus, compared to FIG. 12, the support sleeve 12 can be connected to the fiber core 4 of the first fiber 2 'over a longer length. The support sleeve 12 and the two support disks 24 and 28 together constitute a three-part support sleeve.

  A further variation of the embodiment of FIG. 12 is shown in FIG. In this variant, the support sleeve 12 again has a constant inner diameter over its entire length. The inner diameter is in this case chosen to be somewhat larger than the outer diameter of the fiber sheath 5 of the fiber 2 '. In order to connect the support sleeve 12 to the fiber core 4 of the fiber 2 ′, a further intermediate sleeve 31 is provided, which is connected to the fiber core 4 of the first fiber 2 ′ in a shape-locking and material-bonding manner. . The intermediate sleeve 31 is realized in the same way as the intermediate sleeve 20, apart from its geometric dimensions. The support sleeve 12 is connected to the intermediate sleeve 31 and the intermediate sleeve 23 by a shape lock type and a material bonding type, respectively.

  FIG. 15 shows a design of a splice joint according to the invention, where the support sleeve 12 again has a constant inner diameter over its entire length. The right end surface 29 of the support sleeve 12 is connected to the support disk 32 in a shape-locking and material-bonding manner, and the support disk 32 can be realized in the same way as the second support disk 28 according to FIG. The second fiber 3 ′ is guided in a ferrule 33 (optical fiber core end sleeve), in which case the ferrule 33 has a stepped central bore 34, from the right end of which the second bore 3 ′ A first portion 35 having a constant first inner diameter corresponding to the outer diameter of the fiber core 7, and a second inner diameter adjacent to the first portion and abruptly increasing (this inner diameter is And a second portion 36 having a gradually increasing diameter and at least somewhat greater than the outer diameter of the fiber sheath 5 of the second fiber 2 '.

  The outer diameter of the ferrule 33 is selected so that the support sleeve 12 can be connected to the ferrule 33 by a shape locking method and a material bonding method.

  Furthermore, an intermediate sleeve 31 is provided, which corresponds to the intermediate sleeve of FIG. 14, apart from its geometric dimensions. The intermediate sleeve 31 is connected to the fiber core 4 of the first fiber 2 ′ by a shape lock type and a material bonding type, and the support sleeve 12 is connected to the intermediate sleeve 31 by a shape lock type and a material bonding type.

  The support disks 24 and 28 shown in FIGS. 12-15 are preferably made from the same material as the support sleeve 12. The same applies to ferrule 33.

Claims (12)

A method of creating a splice joint between two optical fibers,
The first and second fibers, which are the two optical fibers, each have a fiber core and a fiber sheath positioned adjacent to the fiber core;
For at least the first fiber of the two fibers, the fiber sheath is completely in a connecting region extending along a predetermined length from the end of each of the fibers to be spliced in the longitudinal direction of the fiber. To remove
Push the support sleeve into one of the two fibers,
Aligning the two ends of the fiber to be spliced together and splicing each other;
Next, the support sleeve
The splice ends of the two fibers are disposed within the support sleeve; and
The portion of the support sleeve that extends beyond the fiber sheath of the first fiber is not located adjacent to the fiber sheath of the first fiber, so that the support sleeve is at least of the first fiber. Extending across the entire connection area beyond the connection area and beyond the fiber sheath of the first fiber;
Push into the splice end,
Mechanically connecting the support sleeve to the fiber core of the first fiber via an intermediate sleeve in the connection region of the first fiber;
Before joining the two fibers, the intermediate sleeve is pushed into one of the two fibers, and after joining the two fibers, the intermediate sleeve is inserted into the fiber core of the first fiber. And then mechanically connecting the support sleeve to the intermediate sleeve.   The method according to claim 1, wherein the mechanical connection between the support sleeve and the intermediate sleeve is realized as a shape lock connection.   The method according to claim 1 or 2, wherein the mechanical connection between the support sleeve and the intermediate sleeve is realized as a connection by material bonding.   The portion of the support sleeve that extends beyond the fiber sheath of the first fiber is not mechanically connected to the fiber sheath apart from an optional end seal. The method according to one item. The fiber sheath is completely removed in each of the connection areas for both of the fibers,
A portion of the support sleeve that extends beyond the fiber sheath of the second fiber is positioned adjacent to the fiber sheath of the second fiber, so that the support sleeve is 5. Pushing into the splice end so as to extend across the connection region of the two fibers, beyond the connection region, and beyond the fiber sheath of the second fiber. The method described in 1.   The method according to claim 5, wherein in the connection region of the second fiber, the support sleeve is mechanically connected directly to the fiber core of the second fiber or via an intermediate sleeve.   7. The portion of the support sleeve that extends beyond the fiber sheath of the second fiber is not mechanically connected to the fiber sheath apart from an optional end seal. the method of. When the support sleeve and the fiber core of the second fiber are directly mechanically connected, the refractive index of the support sleeve is such that the light guided in the fiber core of the second fiber is 8. A method according to claim 6 or 7, wherein the method is selected such that it can be output coupled to the support sleeve via a direct connection. Refractive index of the refractive index and the intermediate sleeve before Symbol support sleeve can be light guided within the fiber core of the first fiber is coupled out to said supporting sleeve via the intermediate sleeve The method according to claim 1, wherein the method is selected as follows.   The method according to claim 1, wherein a support sleeve realized as a volume scatterer and / or a surface scatterer is used as the support sleeve.   11. A method according to any one of the preceding claims, wherein a single support sleeve is used as the support sleeve.   The method according to claim 1, wherein an intermediate sleeve realized as a volume scatterer is used as the intermediate sleeve.

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